Phase 1 randomized double-blind safety and immunogenicity trial of \u3ci\u3ePlasmodium falciparum\u3c/i\u3e malaria merozoite surface protein FMP1 vaccine, adjuvanted with AS02A, in adults in western Kenya

Abstract

We report the first trial of candidate malaria vaccine antigen FMP1, a 42 kDa fragment from the C-terminus of merozoite surface protein-1 (MSP-1) from the 3D7 strain of Plasmodium falciparum, in an endemic area. Forty adult male and female residents of western Kenya were enrolled to receive 3 doses of either FMP1/AS02A or Imovax® rabies vaccine by intra-deltoid injection on a 0, 1, 2 month schedule. Thirty-seven volunteers received all three immunizations and 38 completed the 12-month evaluation period. Slightly more recipients of the FMP1/AS02A vaccine experienced any instance of pain at 24 h post-immunization than in the Imovax® group (95% versus 65%), but otherwise the two vaccines were equally safe and well-tolerated. Baseline antibody levels were high in both groups and were boosted in the FMP1/AS02A group. Longitudinal models revealed a highly significant difference between groups for both the average post-baseline antibody responses to MSP-142 (F1,335 = 13.16; P \u3c 0.001) and the Day 90 responses to MSP-142 (F1,335 = 16.69; P \u3c 0.001). The FMP1/AS02A vaccine is safe and immunogenic in adults and should progress to safety testing in children at greatest risk of malaria